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From: cim2@pyuxv.UUCP (Robert L. Fair)
Newsgroups: net.lang.c
Subject: Boolean datatypes
Message-ID: <210@pyuxv.UUCP>
Date: Thu, 12-Jun-86 19:22:24 EDT
Article-I.D.: pyuxv.210
Posted: Thu Jun 12 19:22:24 1986
Date-Received: Mon, 16-Jun-86 16:38:45 EDT
Organization: CHC
Lines: 23

At the risk of being flamed, I've been using enums for a proper boolean
datatype for years:

	typedef enum { false=0,true } bool;

	bool	flag=false;

	if(!flag)
		...
This has _lots_ of advantages over the usual #defines - especially with
a decent compiler which will barf on constructs like:

	flag=10;	 /* correct syntax error,10 is neither true nor false */
or
	enum	states {activate,inactive,comatose} state;
	flag=state;	 /* correct syntax error - a  state isn't a boolean */

Many current C compilers now implement enums properly (i.e. each enumeration
is a distinct type) yet they are hardly ever used. Any comments why not ?

Rob Fair
Bell Communications Research
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